Autophagy and metacaspase determine the mode of cell death in plants

• Published in: The Journal of cell biology Vol. 203; no. 6; pp. 917 - 927
• Main Authors: Minina, Elena A, Filonova, Lada H, Fukada, Kazutake, Savenkov, Eugene I, Gogvadze, Vladimir, Clapham, David, Sanchez-Vera, Victoria, Suarez, Maria F, Zhivotovsky, Boris, Daniel, Geoffrey, Smertenko, Andrei, Bozhkov, Peter V
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 23.12.2013; The Rockefeller University Press
• Subjects: Apoptosis; Autophagy; Autophagy - physiology; Biologi (Medicinska tillämpningar under 3 och lantbruksvetenskapliga under 4); Caspases - genetics; Caspases - metabolism; Caspases - physiology; Cell Biology; Cell Death - physiology; Cellbiologi; Cytoplasm; Developmental Biology; Evolutionary Biology; Evolutionsbiologi; Models, Biological; Naturvetenskap; Picea - cytology; Picea - genetics; Picea - metabolism; Plant Biotechnology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Proteins - physiology; Proteases; Stress, Physiological; Utvecklingsbiologi; Växtbioteknologi
• ISSN: 0021-9525; 1540-8140; 1540-8140
• DOI: 10.1083/jcb.201307082

Although animals eliminate apoptotic cells using macrophages, plants use cell corpses throughout development and disassemble cells in a cell-autonomous manner by vacuolar cell death. During vacuolar cell death, lytic vacuoles gradually engulf and digest the cytoplasmic content. On the other hand, acute stress triggers an alternative cell death, necrosis, which is characterized by mitochondrial dysfunction, early rupture of the plasma membrane, and disordered cell disassembly. How both types of cell death are regulated remains obscure. In this paper, we show that vacuolar death in the embryo suspensor of Norway spruce requires autophagy. In turn, activation of autophagy lies downstream of metacaspase mcII-Pa, a key protease essential for suspensor cell death. Genetic suppression of the metacaspase–autophagy pathway induced a switch from vacuolar to necrotic death, resulting in failure of suspensor differentiation and embryonic arrest. Our results establish metacaspase-dependent autophagy as a bona fide mechanism that is responsible for cell disassembly during vacuolar cell death and for inhibition of necrosis.